The survey, by a politics professor at Birkbeck University, looks at people who voted for left wing parties in the December general election.
It finds that about half of voters of the Greens and Lib Dems are opposed to the 'trans pledge', but the party worst hit by this is Labour with 27% of their 2019 voters saying they are considering voting for another party due to its pandering to trans activism. The vast majority also oppose the trans pledge.
Labour secured 10.2 million votes last year. This would equate to a loss of nearly 3 million voters. There's no evidence that Labour has generated any support from voters of other parties due to the trans pledge (the Tories secured 14 million votes at that election).
quillette.com/2020/02/27/how-the-trans-pledge-damaged-the-labour-party/